Low profile computer assembly using paired back-to-back peripheral card connectors that support different bus form factors and are mounted on a riser card

ABSTRACT

A low profile riser card assembly for a computer system is provided by incorporating two uniaxial back to back peripheral connectors. The peripheral card connectors extend outwardly along a single axis from opposing sides of a riser card. The riser card is attached to a riser card connector mounted on the circuit board and is held in a perpendicular to the axis and in an upright position with respect to the circuit board. In the assembly of the present single invention, the uniaxial back to back peripheral card connectors are retained on the riser card in a parallel orientation with respect to the riser card connector to produce a low profile computer assembly.

RELATED APPLICATIONS

This is a Continuation of patent application Ser. No. 08/536,907 filedSept. 29, 1995, now U.S. Pat. No. 5,926,378.

BACKGROUND OF THE INVENTION

This invention generally relates to the field of computer systemassemblies and more particularly to the assembly of circuit boardscontained therein.

The increased packaging densities in today's computer assemblies alongwith the increase in market demand for lower profile personal computersystem units has fostered the use of riser card assemblies for attachingperipheral cards to a computer system. Some such assemblies are designedsuch that peripheral cards attach to respective connectors on one sideor on both sides of the riser card.

As shown in FIG. 1, a prior art riser card assembly 100 uses both sidesof the riser card for placing staggered peripheral card connectors onthe sides of a riser card. The assembly 100 includes a main circuitboard 102 upon which a universal connector 105 is placed. A conventionalriser card 110 with electrically conductive metallic circuit traceshaving a mating connector is attached to the connector 105 which holdsthe riser card 110 in an upright position. As shown, the riser card 110has opposing sides 111 and 112 where each side includes one or morestaggered peripheral card connectors 150 for receiving a correspondingnumber of peripheral cards 130. Each peripheral card 130 has a componentside 131 where the electronic circuitry in the form of integratedcircuit chips and discrete components are placed thereon. As depicted,the component side 131 of the peripheral cards 130 plugged into firstside 111 of riser card 110 face a downwardly direction, where as, theperipheral cards 130 with components side 131 plugged into second side112 face an upwardly direction. The conventional staggered connectorarrangement utilizes connectors having rows of pins 151 which attach tothe riser card via corresponding conductive through-holes formed on theopposing surfaces of the riser card 110.

However, with increased demand for lower profile computer system units,the staggered technique for placement of peripheral card connectors oneither side of the riser card no longer permits the achievement of thedesired packaging densities.

Furthermore, with the advent of other bus architectures such as PCI andVESA, known as local bus implementations which may be combined withother personal computer buses such as ISA, there is a need for a singlecomputer system that supports a plurality of peripheral cards havingdiffering form factor specifications.

SUMMARY OF THE INVENTION

Briefly, according to the invention a low profile computer assembly isprovided which is capable of receiving one or more peripheral cards. Thecomputer assembly includes a circuit board having a card connectorplaced thereon for receiving a riser card and holding it in an uprightposition in relation to the main circuit board. Two peripheral cardconnectors are paired together and are attached to the riser card. Thetwo paired peripheral card connectors extend outwardly from opposingsides of the riser card. The connectors extend outwardly along a singleaxis which is substantially perpendicular to the riser card and inparallel to the surface of the circuit board. The assembly includesmeans for electrically coupling and mechanically securing the pairedperipheral cards to the riser card in a parallel orientation with thecard connector.

Additionally the riser card of the present inventory may have auniversal footprint formed on its opposing sides for accommodatingvarious bus form factors.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a prior art riser card having staggeredperipheral card connectors;

FIG. 2 is a view of an exemplary personal computer system incorporatingthe low profile computer assembly of the present invention;

FIG. 3 is side view of a riser card assembly according to the presentinvention;

FIG. 4 is cross sectional along line A--A of FIG. 3;

FIG. 5 is front view of the riser card of FIG. 3 showing peripheral cardconnectors for various buses;

FIG. 6 is side view of another embodiment of the computer assemblyaccording to the present invention with a bus bridge chip;

DISCLOSURE OF THE PREFERRED EMBODIMENT

Referring now to FIG. 2, a personal computer system 200 is shown toinclude a processor unit 202, a display 204, a keyboard 210, a mouse212, a printer 214, a diskette drive 206. Incorporated within theprocessor unit 202 is a personal computer assembly circuit board and oneor more peripheral cards, assembled according to the present inventionto provide a low profile processor unit. It should be noted that,although, the exemplary computer system 200 is shown to be a desktopmodel where the processor unit's longest side is in a horizontalorientation with respect to its supporting surface. However, the presentinvention is equally applicable to a stand-up model where the processorunit's longest side is perpendicular to the supporting surface.Referring to FIG. 3, side view of a non-staggered riser card assembly300 according to the present invention is shown. The assembly 300includes a circuit board 302 having electrical components 303 comprisingIC chips and passive and active components, being electrically connectedto each other according to a specific personal computer designarchitecture, such as well known uni- or multi-processing systemarchitectures. Additional and complementary functions and features areprovided by attaching peripheral cards 330 to the computer system 200.Such peripheral cards 330 may for example comprise hard disk controllersfor enhancing storage capacity of the computer system or communicationdevices for connecting the computer system of the present invention to alocal or a wide area network. As is well known, the peripheral cards 330communicate with the computer system over one or more I/O buses, wheresuch buses comply with specified Input/Output protocols. Each busstandard also specifies a physical form factor which defines among otherthings, a corresponding size, shape and contact spacing. Such I/Oprotocols and form factors may be specified by standard specificationssuch as those relating to ISA, PCL SCSL or Micro Channel. Thespecification for each bus form factor allows peripheral cardmanufacturers to produce cards which could attach to correspondingperipheral card connectors of the computer system.

As shown in FIG. 3, the main circuit board 302 includes a riser cardconnector 305 which is placed on one of its opposing surfaces. A risercard 310 having opposing sides 311 and 312 is inserted into the cardconnector 305 and is held in a substantially upright position withrespect to the main circuit board 302. The riser card 310 includes aplurality of peripheral card connectors 350 disposed on its opposingsides 311 and 312. A plurality of peripheral cards 330 are attached tothe assembly 300 via the peripheral card connectors 350 which extendfrom opposing sides of the riser card 310. The riser card 310 includes aset of electrical contacts 314 formed at its connecting end for couplingto corresponding electrical contacts 316 on the card connector 305. Theriser card 310 may be fabricated from an epoxy glass composite or anyother suitable material with electrically conductive metallic circuittraces (Shown in FIG. 5 by reference numeral 564) The circuit traces aredisposed on the riser card for electrically connecting the circuitry ofthe peripheral cards 330 to the circuitry disposed on the circuit board302 via the peripheral card connector 350 and the riser card connector305. The riser card connector 305 may be formed using thermoplasticpolyester or other suitable material and attached to the main circuitboard 302 via suitable electrical contacts (not shown). As such, theperipheral cards 330 are electrically connected to the circuit board 302via, peripheral card connectors 350, the riser card 310 and the cardconnector 305.

According to the present invention, a low profile computer assembly isprovided by situating two peripheral card connectors 350, havingexemplary height(s) 385 (shown in FIG. 3), width(s) 390 and depth(s) 395(both shown in FIG. 4) in a back to back non-staggered position withrespect to each other. Each connector 350 extends outwardly from acorresponding opposing side 311 or 312 of the riser card 310 along asingle axis A--A which runs perpendicular to the riser card. As such,the back to back uniaxial peripheral card connectors 350 are situated insymmetry with respect to the riser card 310. As shown, the assembly 300may include more than one set of paired connectors, such as the back toback uniaxial pair of peripheral card connectors 355, which aresimilarly situated in a back-to-back uniaxial orientation and extendoutwardly from the opposing sides 311 and 312 along another axis B--Bwhich also runs perpendicular to the riser card 310. Each card connector350 also includes symmetrically opposing contacts 320 for providingelectrical connection to corresponding contacts 321 of the peripheralcards 330.

The back to back uniaxial connectors 350 (or 355) are fastened to theriser card 310 by appropriate retention means, such as screws and nuts,bonding adhesive, etc, to retain the peripheral card connectors 350 in asubstantially parallel orientation with respect to the card connector305: parallel in the sense that a longitudinal axis of a peripheral cardconnector, 350, is parallel to a similar longitudinal axis of the risercard connector, 305. It may be appreciated that the advantages offeredby the assembly of the present invention are derived from back-to-backuniaxial position of the two peripheral cards connectors 350 and theparallel orientation of such connectors with respect to the riser cardconnector 305. The back-to-back arrangement of the connectors 350eliminates the additional height introduced by prior art's staggeredarrangement. In addition, the parallel orientation of the back-to-backconnectors 350 with respect to the card connector 305 makes the heightof the riser card independent of relatively long width 390 of theconnectors 350 and thus, dependent upon substantially short height 385of such connectors. As shown the connectors 350 are attached to theriser card 310 via an screw/nut arrangement 340.

To allow the peripheral card to operate in conjunction with the computersystem of the present invention, the connector contacts 320 of theconnector 350 are electrically coupled to corresponding peripheral cardcontacts 321. The peripheral card contacts 321 are electrically coupledto corresponding electrical contacts 314 via circuit traces 564 (shownin FIG. 5) disposed on one or both sides 311 and 312 of the riser cardutilizing well known circuit board manufacturing techniques.

FIG. 4 is a cross-sectional view, along axis A--A of FIG. 3 of twoperipheral card connectors 350 as they attach to the riser card 310 in aback to back uniaxial manner according to the present invention. Asshown, the peripheral card connectors 350 extend outwardly from theopposing sides 311 and 312 of the riser card 310 along axis A--A andconnect to the peripheral cards 330 to the riser card from one side andto the riser card 310 from the other side. The peripheral card connector350 attached to the riser card circuitry via suitable contacts (notshown). This arrangement positions the peripheral cards 330 insymmetrical situation with respect to the riser card 310. Also shown areperipheral card connector contacts 320, and corresponding peripheralcard contacts 321 which produce the electrical connection between thecomputer system 200 and the peripheral cards 330.

The peripheral card connectors 350 may be provided in a variety ofarrangements. For example, the peripheral card connectors 350 may beintegrated into a single solid piece, such as a molded piece, allowingthem to extend outwardly from the opposing sides of the riser card 310in accordance with the present invention Obviously, in this integratedarrangement, suitable openings must be formed on the riser card 310 toallow the peripheral card connectors 350 to be positioned in substantialsymmetry with respect to the riser card 310. The electrical contacts 320may be formed at the opposing ends of the connector 350 utilizing wellknown molding, electroplating or other suitable connector placementtechniques. The electrical contacts 320 of the connector 350 arepositioned and spaced in accordance with corresponding bus form factor.

For example, for an ISA, PCI or Micro Channel peripheral card theconnector 350 and its electrical contacts 320 may be disposed atopposing surfaces in accordance with their corresponding form factordefinition. Alternatively, the peripheral card connectors 350 may bepositioned against each other in a back to back uniaxial arrangement. Assuch that the opposing contacts 320 extend outwardly along the axis A--Awhile the peripheral card when attaches is positioned perpendicular tothe riser card 310 and in parallel to the circuit board 302. FIG. 4 alsoshows a mechanical fastening arrangement for attaching the connector 350to the riser card utilizing threaded screws, with corresponding nuts forholding the connectors 350 in parallel orientation with respect to theriser card connector 305. However, as described above other suitablefastening means, such as rivets, bonding adhesives, etc., may be used inlieu of the depicted arrangement.

Moreover, it is contemplated that the computer system 200 of the presentinvention be capable of supporting one or more peripheral cards with thesame or differing I/O bus form factors in any combination. Thus, it maybe appreciated that each of the back to back peripheral card connectors350 may be conforming to identical or non-identical form factors. Forexample, the bus form factor on one side of the riser card 310 mayconform to ISA standard while the form factor of the other side mayconform to PCI, or Micro Channel standard. As such, peripheral cardssupporting various I/O configurations may be attached to one or bothsides of the riser card 310.

Referring to FIG. 5, a plan view of one side of the riser card 310 isshown to include a plurality of similarly situated connectors 550, 560,and 565. FIG. 5 also illustrates that because of parallel orientation ofthe peripheral card connectors 350 to riser card connector 305, a numberof parallel pairs of peripheral card connectors may be disposed on theriser card 310 with said number being a function of relatively shortheight 585 of the universal foot print 590 and independent of relativelylong width 580 of the universal foot print of the riser card. Thusallowing a relatively large number of paired back to back peripheralcard connectors being disposed on the riser card 310 with its heightmaintained at a minimum. As shown, the connectors 550, 560, and 565accommodate various I/O form factors while maintaining a uniform anduniversal peripheral card foot print on the riser card 310 forpositioning the back to back uniaxial connectors 350. By maintaining auniversal foot print on the riser card 310 various bus form factors maybe accommodated in one or both sides of the riser card 310 whilemaintaining uniformity in positioning the peripheral card connectors ina back to back uniaxial manner. This arrangement greatly simplifies theattachment requirement of the peripheral card connectors to the risercard as such attachment arrangements could be uniformly applied tosupport various bus form factors. It should be noted that the dimensionsand shapes shown of various buses are exemplary and do not necessarilyillustrate the actual shapes and form factors of the buses discussed. Asshown, pre-defined extension areas 510, 520, and 530 are disposed aroundthe geometry of peripheral card connectors 550, 560, and 565 torespectively accommodate a PCI bus 561, an ISA/EISA bus 562 and MicroChannel bus 563 where such form factors and their respective extensionsform universal foot prints 590 on the riser card (shown with dottedline). According to this aspect of the present invention, the extensionareas of each connector form a universal riser card foot print havingidentical width 580 and height 585 width while accommodating various I/Oform factors. It may be appreciated that the position, size and geometryof the extension areas are defined by the physical specification of acorresponding form factor it accommodates and the specification of theuniversal riser card foot print 590. At each end of the foot print 590,end blocks 555 are formed having openings 556 to accommodate uniformfastening of the peripheral connectors 550, 560, and 565 using identicalthreaded screws and corresponding nuts. As shown, circuit traces 564 aredisposed on the riser card for coupling various components including theperipheral card connectors to each other and the riser card connector305.

Referring to FIG. 6, another embodiment of an assembly 600 according tothe present invention is shown to include an I/O bus bridge chip 601placed on the riser card 310. This arrangement allows functionalinterface between one I/O bus protocol to another I/O bus protocol onthe riser card 310 itself This arrangement greatly enhances support ofvarious I/O bus combinations on the computer system of the presentinvention. That is, various I/O bus combinations may be supported by thecomputer system 200 by simply attaching a suitable riser card 310 to thecard connector 305. For example, a system supporting PCI and MicroChannel buses, may utilize a riser card having PCI/Micro Channel busbridge chip. As such, the I/O bus support configuration of such systemmay be easily changed to for example, a system supporting PCI and ISAbuses, by replacing the previously attached riser card with one havingan ISA/PCI bus bridge chip. As shown, an exemplary Micro Channelperipheral card connector 663 and an exemplary PCI peripheral connector661 may be positioned in a back to back uniaxial orientation and the busbridge chip 601 is placed in close proximity on the riser card 310. Theassembly 600 provides another advantage in that the close proximity ofthe PCI peripheral connector 661 and Micro Channel peripheral connector663 enables peripheral cards 635 and 636 to share data with each otherover a much shorter distance thus contributing to the reliability ofdata transfers over the respective buses.

It should be pointed out that even though, the depicted assembly of thepresent invention is directed toward a desktop personal computer modelwhere the circuit board is substantially parallel to the supportingsurface of the computer system, the assembly of the present inventioncould also be incorporated in a stand-up computer model when the circuitboard is substantially perpendicular to the supporting surface of thecomputer system.

What is claimed is:
 1. A low profile computer assembly, comprising:acircuit board having opposing major surfaces, wherein at least one ofsaid major surfaces includes electrical circuitry disposed thereon; ariser card connector mounted on one of said circuit board major surfacesand being electrically connected to said electrical circuitry; a risercard having opposing first and second sides, said riser card attached tosaid riser card connector and held substantially perpendicular to saidcircuit board, wherein said riser card includes riser card tracesdisposed on at least one of said opposing sides of said riser card forelectrically coupling to said electrical circuitry of said circuit boardthrough said riser card connector; a first edge-card peripheral cardconnector mounted on said first side of said riser card, said firstperipheral card connector extending substantially perpendicularlyoutward from said first side such that said connector is heldsubstantially parallel with respect to said circuit board majorsurfaces, wherein said first edge-card peripheral card connectorincludes edge-card peripheral card contacts electrically coupled to someof said riser card traces, wherein said first edge-card peripheral cardconnector supports a first bus form factor for a first peripheral busconforming to a first bus protocol specification; and a second edge-cardperipheral card connector mounted on said second, opposite side of saidriser card such that said first and second peripheral card connectorsare mounted directly opposed from one another on said first and saidsecond sides of said riser card, whereby said first and secondperipheral card connectors are held substantially parallel with respectto said circuit board major surfaces along a single axis, wherein saidsecond edge-card peripheral card connector includes edge-card peripheralcard contacts electrically coupled to some of said riser card traces,and wherein said second edge-card peripheral card connector supports asecond bus form factor for a second peripheral bus conforming to asecond bus protocol specification.
 2. The low profile computer assemblyof claim 1, wherein said first and second bus form factors aredifferent, and wherein said first and second bus protocol specificationsare different.
 3. The low profile computer assembly of claim 2 furthercomprising an I/O bus bridge circuit placed on said riser card andproviding an interface between said first bus protocol and said secondbus protocol.
 4. The low profile computer assembly of claim 2, whereinsaid first edge-card peripheral card connector supports a first bus formfactor for a first peripheral bus conforming to the peripheral cardinterconnect (PCI) bus protocol specification and wherein said secondedge-card peripheral card connector supports a second bus form factorfor a second peripheral bus conforming to the industry standardarchitecture (ISA) bus protocol specification.
 5. The low profilecomputer assembly of claim 4 further comprising an I/O bus bridgecircuit placed on said riser card and providing an interface betweensaid PCI bus protocol and said ISA bus protocol.
 6. The low profilecomputer assembly of claim 1, further comprising:a first peripheral cardmounted in said first edge-card peripheral card connector conforming tosaid first bus protocol specification and said first bus form factor,said first peripheral card including first and second peripheral cardsides and having first peripheral card circuitry disposed on at leastone of said first or second peripheral card sides, said first peripheralcard circuitry electrically connected to said electrical circuitry viasaid first peripheral card connector, said riser card and said risercard connector; and a second peripheral card mounted in said secondedge-card peripheral card connector conforming to said second busprotocol specification and said second bus form factor, said secondperipheral card including third and fourth peripheral card sides andhaving second peripheral card circuitry disposed on at least one of saidthird or fourth sides, said second peripheral card circuitryelectrically connected to said electrical circuitry via said secondperipheral card connector, said riser card and said riser cardconnector.
 7. A low profile computer assembly, comprising:a circuitboard having opposing major surfaces for disposing electrical circuitryon at least one of said major surfaces, and a riser card connectorplaced on at least one of said circuit board major surfaces and beingelectrically connected to said electrical circuitry; a riser card havingopposing sides, said riser card attached to said riser card connectorand held substantially perpendicular to said circuit board, wherein saidriser card includes riser card traces disposed on at least one of saidopposing sides of said riser card for electrically coupling to saidelectrical circuitry of said circuit board through said card connector;and first and second peripheral card connectors integrated into a singlesolid piece, each of said peripheral card connectors extending outwardlyfrom a respective side of said riser card, wherein said first and secondperipheral card connectors extend outwardly along a single axis whichruns substantially perpendicular to said riser card and substantially inparallel to said circuit board major surfaces, said peripheral cardconnectors including peripheral card contacts electrically coupled tosome of said riser card traces; and wherein said riser card has anopening formed therein to allow said first and second peripheral cardconnectors to be positioned in substantial symmetry with respect to saidriser card.
 8. The low profile computer assembly of claim 7, whereinsaid first peripheral card connector supports a first bus form factorfor a first peripheral bus conforming to a first bus protocolspecification, wherein said second peripheral card connector supports asecond bus form factor for a second peripheral bus conforming to asecond bus protocol specification, wherein said first and second busform factors are different, and wherein said first and second busprotocol specifications are different.
 9. The low profile computerassembly of claim 8 further comprising an I/O bus bridge circuit placedon said riser card and providing an interface between said first busprotocol and said second bus protocol.
 10. A low profile computerassembly, comprising:a circuit board having opposing major surfaces fordisposing electrical circuitry on at least one of said major surfaces,and a riser card connector placed on at least one of said circuit boardmajor surfaces and being electrically connected to said electricalcircuitry; a riser card having opposing sides, said riser card attachedto said riser card connector and held substantially perpendicular tosaid circuit board, wherein said riser card includes riser card tracesdisposed on at least one of said opposing sides of said riser card forelectrically coupling to said electrical circuitry of said circuit boardthrough said card connector; and first and second edge-card peripheralcard connectors mounted back-to-back with respect to each other, each ofsaid edge-card peripheral card connectors extending outwardly from arespective side of said riser card, wherein said first and secondedge-card peripheral card connectors extend outwardly along a singleaxis which runs substantially perpendicular to said riser card andsubstantially in parallel to said circuit board major surfaces, saidedge-card peripheral card connectors including peripheral card contactselectrically coupled to some of said riser card traces; and wherein saidfirst edge-card peripheral card connector supports a first bus formfactor for a first peripheral bus conforming to a first bus protocolspecification, wherein said second edge-card peripheral card connectorsupports a second bus form factor for a second peripheral bus conformingto a second bus protocol specification, wherein said first and secondbus form factors are different, and wherein said first and second busprotocol specifications are different.
 11. The low profile computerassembly of claim 10, wherein said first edge-card peripheral cardconnector supports a first bus form factor for a first peripheral busconforming to the peripheral card interconnect (PCI) bus protocolspecification and wherein said second edge-card peripheral cardconnector supports a second bus form factor for a second peripheral busconforming to the industry standard architecture (ISA) bus protocolspecification.
 12. The low profile computer assembly of claim 10 furthercomprising an I/O bus bridge circuit placed on said riser card andproviding an interface between said first bus protocol and said secondbus protocol.